Normally, in (semi)automatic machines dedicated to the preparation of drinks based on coffee, barley, herbs, flowers or other alimentary products available in grain-size not suited to the related brewing process, suitable grinding devices are provided. Such devices, in both domestic and professional situations, include a housing, a pair of milling heads (at least one of which is revolving) located in the housing, motorized device for driving the revolving milling head, a hopper to feed the food substance (for instance, coffee in beans or grains) between the milling heads, a discharge outlet for the ground or pulverized substance, as well as a mechanism to regulate the distance between the milling heads in order to vary the grain-size of the ground substance.
The milling heads are distinguished on the basis of the shape of their edges and, in general they can be plain, (or concave-concave), conical (or concave-convex), rollers, etc. and they can be arranged one inside the other, or vertically one above the other. The concave-convex milling heads are, for instance, usually arranged concentrically, with the convex milling head inside the concave milling head. The plain milling heads are usually arranged concentrically, one above the other.
In the (semi)automatic machine sector, plain or concave-convex milling heads, given their simplicity, are more widely used, while roller milling heads are more widely employed in the industrial sector. In general, the present invention refers to any type of milling head and is not limited to any particular type of milling head.
Traditionally, the known grinding devices of the type suitable for the uses indicated above are made with poorly modular structures that require precision mechanical machining for their construction, with consequent problems of quality and cost.
As is known, the grain-size of the ground coffee is a particularly delicate parameter in the complex of the parameters required for the preparation of a drink based on coffee, particularly in the case of “espresso” coffee. Likewise, the grain-size of the other alimentary substances cited (barley, flowers for herbal teas, etc.) is also important for the organoleptic characteristics of the drinks prepared starting from such ground substances.
The grain-size, once planned and preset, has to remain as constant as possible over time even if the grinding device has to be dismantled and reassembled for maintenance inspections or for cleaning the parts.
Because the value of the grain-size of the ground coffee or the other ground substances depends in large measure on the distance between the milling heads, the dismantling of the grinding device from the driving motor for maintenance or repair, and the consequent subsequent reassembly, constitutes a non-negligible problem in the known art, in as much as it also includes the dismantling of the milling heads with consequent loss of the grain-size setting.
Furthermore, the known grinding devices, made with poorly modular structures, do not allow the dismantling and the subsequent reassembly without the use of tools, such as, for instance screwdrivers, pliers, spanners and similar.
Since dismantling, according to the known art, also involves parts that come into contact with the food, in the present case the milling heads come into contact with the coffee both as beans and as powder, the necessity to resort to using tools to perform the dismantling and subsequent reassembly is also in conflict with the norms that forbid it.
Automatic machines for the preparation and the dispensing of drinks, have recently appeared on the market endowed with devices for the adjustable grinding of coffee to give the desired grain-size of the coffee powder. In such devices, the grain-size of the grains of coffee is regulated by varying the distance between the milling heads.